/* Generated By:JavaCC: Do not edit this line. CharStream.java Version 0.7pre6 */
/**
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*
* 1. Redistributions of source code must retain copyright
* statements and notices. Redistributions must also contain a
* copy of this document.
*
* 2. Redistributions in binary form must reproduce the
* above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
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* please contact info@exolab.org.
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* 4. Products derived from this Software may not be called "Exolab"
* nor may "Exolab" appear in their names without prior written
* permission of Intalio, Inc. Exolab is a registered
* trademark of Intalio, Inc.
*
* 5. Due credit should be given to the Exolab Project
* (http://www.exolab.org/).
*
* THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2000 (C) Intalio Inc. All Rights Reserved.
*
* $Id$
*/
package org.exolab.castor.xml.dtd.parser;
/**
* This interface describes a character stream that maintains line and
* column number positions of the characters. It also has the capability
* to backup the stream to some extent. An implementation of this
* interface is used in the TokenManager implementation generated by
* JavaCCParser.
* <p>
* All the methods except backup can be implemented in any fashion. backup
* needs to be implemented correctly for the correct operation of the lexer.
* Rest of the methods are all used to get information like line number,
* column number and the String that constitutes a token and are not used
* by the lexer. Hence their implementation won't affect the generated lexer's
* operation.
*
* @author Generated automatically by <b>JavaCC</b>
* @version Version 0.7pre6
*/
abstract public interface CharStream {
/**
* Returns the next character from the selected input. The method
* of selecting the input is the responsibility of the class
* implementing this interface. Can throw any java.io.IOException.
*/
abstract public char readChar() throws java.io.IOException;
/**
* Returns the column position of the character last read.
* @deprecated
* @see #getEndColumn
*/
abstract public int getColumn();
/**
* Returns the line number of the character last read.
* @deprecated
* @see #getEndLine
*/
abstract public int getLine();
/**
* Returns the column number of the last character for current token (being
* matched after the last call to BeginTOken).
*/
abstract public int getEndColumn();
/**
* Returns the line number of the last character for current token (being
* matched after the last call to BeginTOken).
*/
abstract public int getEndLine();
/**
* Returns the column number of the first character for current token (being
* matched after the last call to BeginTOken).
*/
abstract public int getBeginColumn();
/**
* Returns the line number of the first character for current token (being
* matched after the last call to BeginTOken).
*/
abstract public int getBeginLine();
/**
* Backs up the input stream by amount steps. Lexer calls this method if it
* had already read some characters, but could not use them to match a
* (longer) token. So, they will be used again as the prefix of the next
* token and it is the implemetation's responsibility to do this right.
*/
abstract public void backup(int amount);
/**
* Returns the next character that marks the beginning of the next token.
* All characters must remain in the buffer between two successive calls
* to this method to implement backup correctly.
*/
abstract public char BeginToken() throws java.io.IOException;
/**
* Returns a string made up of characters from the marked token beginning
* to the current buffer position. Implementations have the choice of returning
* anything that they want to. For example, for efficiency, one might decide
* to just return null, which is a valid implementation.
*/
abstract public String GetImage();
/**
* Returns an array of characters that make up the suffix of length 'len' for
* the currently matched token. This is used to build up the matched string
* for use in actions in the case of MORE. A simple and inefficient
* implementation of this is as follows :
* <pre>
* {
* String t = GetImage();
* return t.substring(t.length() - len, t.length()).toCharArray();
* }
* </pre>
*/
abstract public char[] GetSuffix(int len);
/**
* The lexer calls this function to indicate that it is done with the stream
* and hence implementations can free any resources held by this class.
* Again, the body of this function can be just empty and it will not
* affect the lexer's operation.
*/
abstract public void Done();
}